ERBB2 and breast cancer: Aiming to developa HER-2-targeting polymersome to deliver DM1for breast cancer therapy, we therefore designed an amphiphilic blockcopolymer consisting of PG, PTMC, and dithiolaned PTMC to formulatemultifunctional polymersomes via a “one-pot” strategy.The potent anticancer drug DM1 was covalently anchored inside vesiclesduring the self-assembly and self-cross-linking of the block copolymer.To target HER-2-positive cancer, postengineering of the ligand trastuzumabto the surface of polymersomes was carried out by click chemistry(Scheme 1).